As is well known in the art electrical cables having a multitude of helically wound armour wires can easily be anchored against tensile forces exerted on the cable by means of the well known armour clamp comprising a cone and co-operating complementary thimble between which the armour wires are clamped firmly in use.
However, where the armouring assumes the form of a metal strip, which may be grooved so that co-operating edge portions overlap to form a continuous armour sheath, such a form of armour clamp is inappropriate and, indeed, ineffective. Where such grooves are not present two flat strips can be employed with the outer one covering a helical gap between successive convolutions of the inner one.
In an effort to solve this problem there has been proposed, in South African Pat. No. 79/2062, a cable gland in which a deformable lead ring is deformed to contact with the inner regions of grooves provided in an armouring strip of a grooved configuration in an effort to anchor such armouring axially. However, in view of the deformable nature of the lead, anchoring is not effective and the armouring can, in fact, be pulled axially from the cable gland. In that particular case the gland is made for co-operation with a cable having an inner lead sheath and the lead sheath is soldered to a body of lead provided in the cable gland.
This latter arrangement effectively connects, electrically, the gland with the lead sheath. However, when such a gland must be removed, for example for the purpose of servicing or repairing electrical equipment served by a cable associated with a gland of this nature, the lead and solder must be melted before the cable can be released from the cable gland. This often involves the use of a flame which is totally inconvenient in the case where such flame represents a fire or explosion hazard.
It is the object of this invention to provide an improved cable gland of the above described nature in which a vastly improved axial holding force is afforded the armouring of a cable operatively associated therewith and, in the case where a cable has a lead sheath, a more simple electrical connection is effected to the lead sheath.